Fix short-circuiting when TSDInfo not present, preventing reading DTVInfo#1294
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christos68k merged 3 commits intoopen-telemetry:mainfrom Mar 31, 2026
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- Only error out if BOTH reads fail - Only set the value if not an error on read - Add a regression test that builds an mock ELF file to verify the correct behaviour
dalehamel
commented
Mar 27, 2026
| // buildTestELF creates a minimal 64-bit ELF binary with the given dynamic symbols. | ||
| // Each symbol maps to its corresponding code byte slice. The resulting ELF has a | ||
| // SysV hash table so pfelf.File can resolve symbols via LookupSymbol/SymbolData. | ||
| func buildTestELF(t *testing.T, machine elf.Machine, symbols map[string][]byte) *pfelf.File { |
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This is a bit heavy but I wanted to be sure that this regression was caught cleanly. It might be useful elsewhere, but for now i think this is an OK spot for it.
Disclaimer: I had AI help me write this in order to add the test.
florianl
approved these changes
Mar 30, 2026
Co-authored-by: Florian Lehner <florianl@users.noreply.github.com>
christos68k
approved these changes
Mar 31, 2026
| }, nil | ||
| // Return an error only if both extractions failed. | ||
| if tsdErr != nil && dtvErr != nil { | ||
| return nil, fmt.Errorf("TSD: %s; DTV: %s", tsdErr, dtvErr) |
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Nit: Maybe it's better to introduce TSDError and DTVError inside extract{TSD,DTV}Info and then a simple errors.Join here.
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What
Updates ExtractLibcInfo to:
Why
In #929, I incorrectly added short circuiting where we would fail to read the DTV.
During the review of #1226, the first actual use of the DTV, @nsavoire correctly pointed this out (thank you!)
I recall that in an earlier version of the branch, I had anticipated this and just logged an error, but then in subsequent refactoring and addressing feedback this must have gotten lost.
To avoid this from happening again, I've added a regression test which actually calls
ExtractLibcInfowith a stub ELF binary for testing purposes to prove that it correctly still reads the DTV in this edge case where the DTV and TSD are in separate binaries, so we can actually merge them.My apologies for the oversight, between reviews and switching tasks I forgot about this edge case.